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On-line version ISSN 1678-8060
Mem. Inst. Oswaldo Cruz vol.89 no.2 Rio de Janeiro Apr./Jun. 1994
Reversibility of muscle and heart lesions in chronic Trypanosoma cruzi infected mice after late trypanomicidal treatment
Universidad Nacional de Salta, Facultad de Ciencias Naturales, Salta, Argentina
Universidad Nacional de Salta, Facultad de Ciencias de la Salud, Laboratorio de Patologia Experimental, Salta, Argentina
The effect of trypanomicidal treatment upon established histopathological Trypanosoma cruzi induced lesions was studied in Swiss mice. The animals were inoculated with 50 trypomastigotes and infection was allowed to progress without treatment for 99 days. After this period, the animals were divided in three groups, treated for 30 days with either placebo, benznidazole (200 mg/kg/day) or nifurtimox (100 mg/kg/day). These treatments induced 94 and 100 (per cent) cure rates respectively as detected by xenodiagnosis and reduction of antibody levels. Autopsies and histopathological studies of heart, urinary bladderand skeletal muscle performed on day 312 after infection showed almost complete healing without residual lesions. As long periods were allowed between infection, treatment and autopsy, the results indicate that tissue lesions depend, up to advances stages, on the continuous presence of the parasite.
Key words: Trypanosoma cruzi; chronic infection; chemotherapy; histopathology